/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache license, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the license for the specific language governing permissions and * limitations under the license. */ package org.apache.logging.log4j.core; import java.io.Serializable; /** * Appends log events. An Appender can contain a {@link org.apache.logging.log4j.core.Layout} if applicable as well * as an {@link org.apache.logging.log4j.core.ErrorHandler}. Typical Appender implementations coordinate with an * implementation of {@link org.apache.logging.log4j.core.appender.AbstractManager} to handle external resources * such as streams, connections, and other shared state. As Appenders are plugins, concrete implementations need to * be annotated with {@link org.apache.logging.log4j.core.config.plugins.Plugin} and need to provide a static * factory method annotated with {@link org.apache.logging.log4j.core.config.plugins.PluginFactory}. * *
Most core plugins are written using a related Manager class that handle the actual task of serializing a * {@link org.apache.logging.log4j.core.LogEvent} to some output location. For instance, many Appenders can take * advantage of the {@link org.apache.logging.log4j.core.appender.OutputStreamManager} class.
* *It is recommended that Appenders don't do any heavy lifting since there can be many instances of the class * being used at any given time. When resources require locking (e.g., through {@link java.nio.channels.FileLock}), * it is important to isolate synchronized code to prevent concurrency issues.
*/ public interface Appender extends LifeCycle { /** * Logs a LogEvent using whatever logic this Appender wishes to use. It is typically recommended to use a * bridge pattern not only for the benefits from decoupling an Appender from its implementation, but it is also * handy for sharing resources which may require some form of locking. * * @param event The LogEvent. */ void append(LogEvent event); /** * Get the name of this Appender. * * @return name, may be null. */ String getName(); /** * Returns the Layout used by this Appender if applicable. * * @return the Layout for this Appender or {@code null} if none is configured. */ Layout extends Serializable> getLayout(); /** * Some Appenders need to propagate exceptions back to the application. When {@code ignoreExceptions} is * {@code false} the AppenderControl will allow the exception to percolate. * * @return {@code true} if exceptions will be logged but not thrown, {@code false} otherwise. */ boolean ignoreExceptions(); ErrorHandler getHandler(); void setHandler(ErrorHandler handler); }